Previous studies of the mode of action of antischistosomal drugs have suggested that tight-binding inhibitors of acetylcholine binding sites might have selective toxic effects in schistosomes. Hycanthone may act by virtue of such a mechanism. For this reason we propose to synthesize a series of alkylating analogs of acetycholine, and to test these agents on the cholinergic pharmacology of schistosomes will be compared with their effects on vertebrate systems, using standard guinea pig and frog muscle preparations. These studies will provide entirely new information concerning the binding specificity of schistosomal receptors and will provide a basis for further drug development activities.